In the present paper we consider the nonlinear superposition operator \(F\) in Banach spaces of sequences \(l_p\) \((1\le p\le \infty)\), generated by the function \(f(s, u) = d(s) + a^{ku} - 1\), with \(a > 1\) and \(k\in \mathbb{R}\setminus\{0\}\). We find out the Rhodius spectra \(\sigma_R(F)\) and the Neuberger spectra \(\sigma_N(F)\) of these operators, depending on the values of \(k\).

In this paper, we consider the topic from the theory of cosine operator functions in 2-dimensional real vector space, which is an interplay between functional analysis and matrix theory. For the various cases of a given real matrix A= [α , β; γ , δ] we find out the appropriate cosine operator function C(t)= [a(t), b(t); c(t), d(t)], (t \in R) in a real vector space R2 as the solutions of the Cauchy problem C''(t)=AC(t), C(0)=I, C'(0)=0.

Abstract Financial literacy has become an interesting topic recently, given the global trends and the need for individuals to take responsibility for their personal finances and, in particular, for their retirement planning. In this paper we investigate financial literacy of adults in Bosnia and Herzegovina. Our survey questionnaire is based on the OECD/INFE questionnaire, with some adjustments to national specificities. The method of research is the online survey. Looking at the results, our research overall shows rather low level of financial literacy of Bosnian citizens. In particular, low level of understanding and skills related to basic concepts, such as compound rate of return and diversification, indicate that there are many aspects of financial knowledge that could be improved. Financial knowledge and behavior of our sample is better positioned than the average in other countries. Due to worse attitude, the overall level of financial literacy is lower than the average in other countries. In addition, the analysis showed that attitudes towards the money are worse than the attitudes of citizens in other countries. Looking at at different levels of income, we notices no statistically significant difference in behavior and attitudes within different groups. The low level of financial literacy emphasizes the importance of introducing financial education at an earlier age, since the lack of financial education can cause people to start saving later in life, thus limiting required retirement goals. As a result, it is unlikely to achieve an optimal balance between current consumption during work and future consumption as individuals retire. In addition, the lack of information on the distribution of risk and return on various investments can lead to the misallocation of their pension portfolios.

IntroductionData on management of atrial fibrillation (AF) in the Balkan Region are scarce. To capture the patterns in AF management in contemporary clinical practice in the Balkan countries a prospective survey was conducted between December 2014 and February 2015, and we report results pertinent to the use of non-vitamin K antagonist oral anticoagulants (NOACs).MethodsA 14-week prospective, multicenter survey of consecutive AF patients seen by cardiologists or internal medicine specialists was conducted in Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Montenegro, Romania, and Serbia (a total of about 50 million inhabitants).ResultsOf 2712 enrolled patients, 2663 (98.2%) had complete data relevant to oral anticoagulant (OAC) use (mean age 69.1 ± 10.9 years, female 44.6%). Overall, OAC was used in 1960 patients (73.6%) of whom 338 (17.2%) received NOACs. Malignancy [odds ratio (OR), 95% confidence interval (CI) 2.06, 1.20–3.56], rhythm control (OR 1.64, 1.25–2.16), and treatment by cardiologists were independent predictors of NOAC use (OR 2.32, 1.51–3.54) [all p < 0.01)], whilst heart failure and valvular disease were negatively associated with NOAC use (both p < 0.01). Individual stroke and bleeding risk were not significantly associated with NOAC use on multivariate analysis.ConclusionsNOACs are increasingly used in AF patients in the Balkan Region, but NOAC use is predominantly guided by factors other than evidence-based decision-making (e.g., drug availability on the market or reimbursement policy). Efforts are needed to establish an evidence-based approach to OAC selection and to facilitate the optimal use of OAC, thus improving the outcomes in AF patients in this large region.

In this paper, we consider the nonlinear superposition operator F in lp spaces of sequences (1 ≤ p ≤ ∞), generated by the function f(s,u)=a(s) + arctan u or f(s,u) = a(s) - arctan u. We find out the Rhodius spectra σR(F) and the Neuberger spectra σN(F) of these operators and finally the radii of these spectra. The superposition operator generated by the function f(s,u) = a(s) ∓ arccot u appears to be a special case of above mentioned operator.

Data on the management of atrial fibrillation (AF) in the Balkan Region are limited. The Serbian AF Association (SAFA) prospectively investigated contemporary ‘real-world’ AF management in clinical practice in Albania, Bosnia&Herzegovina, Bulgaria, Croatia, Montenegro, Romania and Serbia through a 14-week (December 2014-February 2015) prospective, multicentre survey of consecutive AF patients. We report the results pertinent to stroke prevention strategies. Of 2712 enrolled patients, 2663 (98.2%) with complete data were included in this analysis (mean age 69.1 ± 10.9 years, female 44.6%). Overall, 1960 patients (73.6%) received oral anticoagulants (OAC) and 762 (28.6%) received antiplatelet drugs. Of patients given OAC, 17.2% received non-vitamin K antagonist oral anticoagulants (NOACs). CHA2DS2-VASc score was not significantly associated with OAC use. Of the ‘truly low-risk’ patients (CHA2DS2-VASc = 0 [males], or 1 [females]) 56.5% received OAC. Time in Therapeutic Range (TTR) was available in only 18.7% of patients (mean TTR: 49.5% ± 22.3%). Age ≥ 80 years, prior myocardial infarction and paroxysmal AF were independent predictors of OAC non-use. Our survey shows a relatively high overall use of OAC in AF patients, but with low quality of vitamin K antagonist therapy and insufficient adherence to AF guidelines. Additional efforts are needed to improve AF-related thromboprophylaxis in clinical practice in the Balkan Region.